High speed printing system



y 1963 c. A. CHRISTOFF ETAL 3,090,298

HIGH SPEED PRINTING SYSTEM Filed Feb. 5, 1962 4 Sheets-Sheet 1 INVENTORS CHE/8 A. ewe/s 70, JOHN D. GEAE/(EAET BY E/CHAED E. 50 CH ATTORNEY May 21, 1963 Filed Feb. 5, 1962 C. A. CHRISTOFF ETAL HIGH SPEED PRINTING SYSTEM 4 Sheets-Sheet 2 I N VEN TORS (Me/5 4. CMISTOFF JOHN L2 GEAEl-IEAET PEI-MED 1 BUS C H May 21, 1 c. A. CHRISTOFF ETAL HIGH SPEED PRINTING SYSTEM 4 Sheets-Sheet 3 Filed Feb. 5, 1962 PIE Q;

INVENTORS (MG/J A. C/(E/STGFF JOHN a GEAEl-(EAET BIC/{4RD E. suscH y 1953 c. A. CHRISTOFF ETAL 3,090,298

HIGH SPEED PRINTING SYSTEM Filed Feb. 5, 1962 4 Sheets-Sheet 4 FIE COMPARISON COMPARISON I NVENTORS (HE/S ,4. are/s TOFF JOHN a GEAR/164E? PIC/{142D E. BUS C H nan o- 3,090,298 Patented May 21, 1963 3,090,298 IHGH SPEED PRINTING SYSTEM Chris A. Christotf, San Gabriel, John D. Gearheart, Tempie City, and Richard E. Busch, La Puente, Califi, assignors to Clary Corporation, San Gabriel, Calif., a corporation of California Filed Feb. 5, 1962, Ser. No. 170,930 9 Claims. (Cl. 101-933) This invention relates to high speed printers or recorders of the so-called print-on-the-fly type wherein a printing drum carrying type elements spaced around its periphery is continually moved past a recording device. Such drum may be rotated at a continuous speed as disclosed, for example, in the Hartley Patent No. 2,776,618 issued on January 8, 1957 or it may be constantly moved in a non-uniform or hypocycloidal manner as disclosed and claimed in the Witt et al. Patent No. 2,915,968, issued on December 8, 1959.

Printers of the above type are capable of relatively high speeds. However, time must be allowed for advancement of a record medium after each line of print has been completed. Generally, such printers provide for spacing of the record medium to a new print line near the end of a current cycle as shown, for example, in the above Hantley and Witt et al. patents.

Accordingly, a blank space is usually left on the drum between the last of one series of type elements and the beginning of the same or the beginning of a new series of type elements to permit advancement of the record medium as such blank spaces pass the printing point. In other cases, relatively complicated electronic circuitry must be provided to inhibit recording during the record medium advancing phase of a printing cycle. Thus, in commencing a printing operation, printing is generally withheld until a definite starting position on the drum reaches the printing point.

Although the printing drums of print-on-the-fly type printers move at relatively high peripheral speeds, an appreciable time is wasted in inhibiting the printing operation until the starting point on the drum has reached the printing point.

Accordingly, a principal object of the present invention is to provide a printer of the above type wherein printing may commence any time during movement of the printing drum past the printing point.

Another object is to provide a printer of the above type in which no blank spaces need be provided on the printing drum to permit operation of the advancing mechanism for the record medium.

Another object is to provide a printer of the above type which may be connected on-line with an electronic com puter or similar apparatus with a minimum of delay in starting the printing operation.

The manner in which the above and other objects of the invention are accomplished with be readily understood on reference to the following specification when read in conjunction with the accompanying drawing, wherein:

. IG. 1 is a transverse sectional view through a printer embodying a preferred form of the present invention and is taken along the line 11 of FIG. 3.

FIG. 2 is a sectional view through the printing drum unit and is taken along the line 22 of 'FIG. 3.

FIG. 3 a sectional plan view of the printer and is taken along the line 33 of FIG. 1.

FIG. 4 is a side elevation view illustrating the mechanism for transmitting motion to the different units of the printer and is taken substantially along the line 4-4 of FIG. 3.

FIG. 5 is a sectional view illustrating the printer clutch and is taken along the line 55- of FIG. 3.

FIG. 6 is a sectional view illustrating the ratchet feed mechanism for advancing the paper from one print line to the next and is taken along the line 6-6 of FIG. 3.

FIG. 7 is a schematic view illustrating the control circuitry for the printer.

The particular printer drum unit illustrated in connection with the present invention is disclosed in detail in the above Witt et al. patent and therefore reference may be had to such patent for a complete disclosure of the unit. It is to be understood, however, that the invention could equally well be applied to any type of print-on-the-fiy printer wherein a type drum is constantly moved past a printing point.

Referring to the drawings, the printer comprises a base 11 having three upstanding side walls 12, '13 and 114 on or between which various units of the printer are mounted.

A hollow cylindrical printing drum 14 is mounted through ball bearings i.e. 15 (FIG. 2) on eccentric shaft portions 16 formed adjacent opposite ends of a rotatable drive shaft v17, the latter being suitably mounted for lo cation in bearings (not shown) carried by bearing housings 18 and 19 supported by the walls 12 and 13, respectively. A plurality of columns of type elements 20 are formed around the periphery of the drum. The type elements are arranged in 24- equally spaced rows of type elements, each row extending lengthwise of the drum and containing identical type. The type elements in each column are arranged in two progressive series of 12 elements each ranging in value from 0 to 9 with two additional symbol type.

A stationary internal gear 21 is formed concentrically of the shaft 17 proper in the bearing housing 18 and meshes with an external gear 22 formed integrally with the drum 14 and extending concentrically therewith.

The ratio between the number of teeth of gear 21 and the number of teeth of 22 is such that as the drum orbits about the axis A of the shaft 17 in one direction the drum will advance in the opposite direction an amount equal to the spacing between two adjacent rows of type elements during each revolution of the shaft 17.

Thus, during each revolution of the drive shaft, a new row of type elements 20 will be moved to a printing point or station formed by a row of type platens 24.

The platens 24 are slideable in guide slots formed in a guide block 25 suitably fixed to the base '11. Each of the platens is pivoted at 26 to an armature 27 which, in turn, is pivotally supported at 28 to cooperate with a respective electromagnet 30. Normally, each platen 24 is held in its lower position illustrated in FIG. 1, out of printing relation with the drum, by a tension spring 31 extending between the respective armature and a stationary stud 3 2. However, upon energization of the associated magnet 30, as will be described later, the platen will be raised sufiiciently so that as the drum moves downward in a hypocycloidal motion, during its orbital movement about the center of the drive shaft, it will effect a printing contact with the platen so as to transmit a printing impression from a particular type element aligned with the platen onto a strip of paper 33. Suitable means including an inking roller 29 are provided to apply a film of ink to the surface of the type elements.

The paper strip is in fan-fold form and is provided with sprocket perforations '34 (FIG. 3) along its edges whereby it may be fed forwardly through the printer by a feed sprocket 35. The latter is rotatably mounted in bearings carried by the walls 12 and 13 and is effective to draw the paper from a supply pack 36 and to advance the same between the printing drum '14 and the row of platens 24, from one printing line position to the next.

The printer is driven by an electric motor 38 which acts to constantly advance the drum 14 past the printing station. For this purpose, a sprocket 40 (FIG. 4) on the motor shaft drives a cog belt 41 which, in turn, drives the intermediate unit of a compound sprocket 42 rotatably mounted on a frame stud 43. The larger unit of the sprocket drives a sprocket 44 fastened to the drive shaft 17 through a cog belt 45. The smaller unit of the sprocket 42 drives a sprocket 46 rotatably mounted on a shaft 49, concentric of the paper feeding sprocket 35, and a second sprocket 47 through a cog belt 48. An idler Wheel 50 maintains the belt 48 in intimate driving engagement with the sprockets 46- and 47.

The ratios of the diameters of the various cog belt sprockets are such as to drive the shaft 17 twelve revolutions during each revolution of the sprocket 47 so that the drum 14 will advance twelve rows of type elements past the printing station during each revolution of sprocket 47.

Means are provided to advance the paper strip 33 after printing a line of characters, and for this purpose the sprocket 46 is attached to a rachet wheel 52 (FIGS. 3 and of a cyclic clutch generally indicated at 53. The rachet wheel has 14 equally spaced notches 152 therearound. A drive pawl 54 having a drive tooth 54a is pivotally mounted at 55 on a driven clutch disc 56, which disc is attached to the shaft 49. The shaft is rotatably mounted in bearings carried by the feed sprocket 35 and the wall 114.

The pawl 54 is normally held out of engagement with the rachet wheel against the action of a torsion spring 57, by a clutch dog 58 which is pivoted at 60 and normally latches a camming disc 61 rotatably mounted on the shaft 49 and provided with a camming surface underlying a stud 62 on the pawl.

A cam 63 is suitably attached to the shaft 49 and cooperates with a cam follower 64. The latter is fulcrumed at 65 and is urged into engagement with the cam by a torsion spring 66. The cam follower is piv-otally connected through a link 67 to a pawl 68 pivotally supported by an arm 70 which is free on the shaft 49. A torsion spring 71 yieldably maintains the pawl 68 in driving engagement with a rachet wheel 72. fastened to the paper feed sprocket 35.

The clutch dog 58 forms an armature which cooperates with an electromagnet 73. Thus, upon energization of the magnet, as will appear later, to release camming disc 61 and thus the pawl 54 to the action of its spring 57, the clutch 53 will become engaged to complete a cycle or 360. It will be noted that the tip of the cam 63 normally, when the clutch is in full cycle position, rests under the cam follower 64 so that at the cornmencement of a clutch cycle the pawl 68 will rasp back over a tooth of the rachet wheel 72, during which time retrograde movement of the paper feeding sprocket 35 is prevented by a back up preventing pawl 74. During the latter stages of the clutch cycle, cam 63 will be effective to drive the cam follower 64, and therefore pawl 68, to advance the paper feed sprocket from one printing line position to the next.

As shown in FIGS. 3, 4 and 7, the sprocket 47 carries a two pronged electrical brush 75 which wipes over a stationary commutator 76 suitably attached to thewall 13. One prong of the brush wipes over twelve equally spaced contact segments 77 which are insulated from each other, there being one contact segment for each row of type elements on the drum. The other prong wipes over a contact or slip ring 79 connected to a source of appropriate potential. The contact segments 77 are connected through respective lines 78 to the inputs of a decimal-to-binary converter 80. The latter may be of any Well known design having. a four line binary coded output trunk 81 which is connected to one set of. four inputs 181 of each of-a series of comparison gates 82. The latter are associated with an electronic data registering device 83 which may be a parallel output type electronic computer or the like having a binary coded decimal output.

Each denominational decade output of the computer 33 is provided with a set oil four binary coded lines 183 which are connected as a second input set to the corresponding comparison gate 82. Although only three comparison gates 82 and their connections to the output trunk 81 and to respective output lines of the computer $3 are shown, it will be understood that there will normally be one comparison gate for each denominational decade of the computer.

Although any suitable comparison gate circuitry capable of comparing two sets of binary coded signals may be employed which will produce a signal on an output line 85 when the input signals of each set coincide, reference may be had to FIG. 5 of the copending London application, Serial No. 802,778, filed March 30, 1959, for an illustration of an exemplary comparison gate circuit.

The driven clutch disc 56 carries an electrical brush 86 (FIGS. 5 and 7) which wipes over a second stationary commutator 87 attached to the wall 114. The commutator has 14 spaces equally spaced therearound, the first 12 of which are occupied by contact segments 88 connected together to apply successive timing pulses over a line 90 when the clutch is engaged. The 13th and 14th spaces contain a timing contact 91 connected through line 92 to one input of an and gate 93 and a stop contact 94 connected through line 95 to the reset input R of a trigger or flip-flop circuit 119.

It will be noted that the brush 86 is two pronged, one prong of which wipes over the various contacts 88, E1 and 94 while the other prong wipes over a contact ring 89 connected to a source of appropriate potential. Also, the brush 86 is normally located between the stop contact 94 and the number one or first timing contact '88 when the clutch is in full cycle position.

The ratios of the diameters of the various sprockets of FIG. 4 are such that when the clutch 53 is engaged the brush 86 will advance from one contact 88 to the next as the brush 75 advances from one contact 77 to the next. However, since there are 14 equal spaces on the commutator 87, the printing drum and brush 75 will actually advance 14 contact spaces or one and one sixth revolutions during each cycle of the clutch.

From the foregoing it will be seen that when a type element in a particular column of the printing drum passing into proximity with the printing station corresponds to a character represented by the output of the respective decade of the register device 83, a signal will be applied from the output of the associated comparison gate 82 to one input of an and gate 97 whose output is connected through a suitable amplifying circuit to the platen positioning magnet 30, thereby conditioning the and gate to transmit a print signal. Also, two or more such gates 97 may be concurrently conditioned if two or more similar characters are to be printed in the same print line.

The control circuitry for the printer will be described in terms of logic wherein the term true signifies one form or level of potential and false signifies another form or level of potential.

Upon receipt of a steady state true signal from the computer 83 or other sourceover line 99, calling for a print operation, the signal will be passed by an or gate 93 and will be inverted to a false signal by an inverter circuit 100. The latter signal will be applied over line 101 to one input of an and gate 132.

Control trigger circuits or flipdlops 103 and 104 are provid'ed. These are of the type which are set and reset by separate true input signals and when in one such condition or the other apply steady state output signals on the corresponding outputs thereof. That is, when in reset condition, the left hand output thereof will produce a true signal and the right hand output will produce a false signal. When in set condition the output signals are reversed.

Normally, at the start of a print operation the flip-flops 103 and 104, as Well as a third flip-flop 119, are in reset conditions wherein their left hand or reset outputs are true. Accordingly, a true signal will be applied from the reset output of flip-flop 103 to one input of an and gate 105. Concurrently, the false print command signal produced by inverter 100 will be inverted by inverter 106, and will be transmitted as a true signal to gate 105 where it will now be passed to energize the electromagnet 73 and thus cause engagement of the clutch 53. This may obviously occur in any position of the type drum relative to the printing station but as the clutch pawl 54 drops into the nearest notch 152 in the clutch disc 52, the brush 86 will operate in synchronism 'with brush 75. At this time, a true signal will be transmitted by the reset output of flip-flop 104 over line 120 and inverter 121 to the computer to prevent the computer from changing the data appearing on the output lines 1 83 thereof. Also, at this time, a false signal will be applied by flip-flop 119, over line 108, and through an or gate 109 and two inverter circuits 110 and 111, located in tandem, to hold a second input of the gate 102 false. The latter gate is effective only upon receiving false signals on all inputs thereof to transmit a false signal which is inverted by inverter 180 and applied as a true signal to the second inputs of all of the gates 97.

As the brush 86, in moving counterclockwise from its full cycle position shown in FIG. 7, reaches the first contact 88 concurrently with passage of a row of type elements into proximity with the printing station, a true signal will be applied from contact ring 89, over brush 86 and line 90 to set the flip-flop 103, applying a false signal to the gate 105 to deenergize the magnet '73. However, the clutch will continue through its cycle.

Also, an inverter circuit 112 acts to apply the signal as a false signal to the third input of the and gate 102. The latter Will now apply a false signal to the inverter 180 which transmits the same as a positive signal to the second inputs of all of the and gates $7. Thus, any conditioned gate or gates will pass a print signal to eifect printing of that type element or elements on the drum representing characters registered by the corresponding outputs of the electronic computer 83.

It should be noted that the time period during which the brush 86 is in engagement with each contact 80 is less than the time period during which the brush 75 is in engagement with each contact 77, whereby the contacts 88 control the duration of time that the magnets 30 are energized.

The brush 86 will successively apply control signals to the gates 97 as the different rows of type elements pass into proximity of the printing station to effect printing of different characters registered by the computer. After passage of a complete series of twelve such rows, i.e. a complete revolution of the printing drum regardless of the starting point or row, the brush 86 will engage a contact 91, applying a true reset signal over line 92 to the and gate 93. At this time a true signal will have been applied to a second input of the gate 93 by the set flipflop 103. Since the flip-flop 119 is normally in reset condition, the third input of gate 93 will be set true, permitting gate 6 to pass a true signal to set flip-flop 104. Ac-

cordingly, a signal will be applied over line 120' and inverter 121 to enable the computer to apply a new set of data to its output lines 183 and to change the steady state print command signal over line 99' to false. The inverter 100 will now apply a true signal over line 101 to reset flipfiops 103 and 104.

As brush 86 engages stop contact 94, a true signal will be applied over line 95 to reset flip-flop 119 in the event it has been set as will be described presently.

It will be noted that the actual paper advance ctfected by cam 63 (FIG. 6) occurs during passage of the brush 36 beyond the last contact 88a, i.e. after the drum 14- has made one complete revolution.

Means are provided whereby a true paper space signal applied over a line 115 from the computer 83 or other source will effect engagement of the clutch to space the paper while preventing printing. For this purpose, the paper space signal is fed through the or gate 109, inverters 110 and 111, or gate 98 and inverters 100 and 106 to the and gate thus energizing the clutch control magnet 73 in the same manner as noted above. However, since the and gate 102 is held closed at this time by application of a true signal thereto by inverter 111, the and gates 97 will not be enabled topass print signals to the magnets 30.

In order to permit manually controlled paper spacing at any time that the printer is not in operation, a push button switch 116 is provided which is elfective upon depression to transfer a true signal to one input ofan and gate 117. The other input of gate 117 is connected to line 101 which is normally held true by the inverter 100 in the absence of a true print command signal from the computer so that the flip-flop 119 will be set at this time, thus transferring a true signal over line 108 to or gate 109 so as to effect a paper space operation in the same manner as previously noted in connection with the paper space signal from the computer while inhibiting printing. Near the end of the clutch cycle, the brush 86 will transmit a true signal over contact 94 and line 95 to reset the flip-flop 119.

Although the invention has been described in detail and certain specific terms and languages have been used, it is'to be understood that the present disclosure is illustrative rather than restrictive and that changes and modi fications may be made without departing from the spirit or scope of the invention as set forth in the claims appended hereto.

Having thus described the invention, what is desired to be secured by United States Letters Patent is:

1. In a high speed recording system including a character recording device movable into different recording positions for recording different respective characters at a recording stat-ion, means for constantly advancing said recording device repetitively through said positions, and normally disabled recording control means for effecting recording by said recording device; the combination comprising a comparison device having two inputs and an output for transmitting a recording signal when two similar signals are received by said inputs, means for transmit-ting a signal representative of a character to be re- .corded by said recording device to one of said inputs,

means operable synchronously with said recording device for transmitting a signal to the other of said inputs representative of the recording character instantly in proximity to said recording station, a cyclically operable timing device having a number of timing positions equal to the number of said different recording positions, normally disabled means for advancing said timing device through said timing positions in synchronism with movement of said character recording device through said recording positions, means controlled jointly by said timing device when moving through said timing positions and by a said recording signal for enabling said recording control means, and means for enabling said timing device advancing means at any time during advancement of said recording device.

2. In a high speed recording system including a character recording device movable into different recording positions for recording different respective characters at a recording station, means for constantly advancing said recording device repetitively through said positions, and normally disabled recording control means for efifecting recording by said recording device; the combination comprising a comparison device having two inputs and an output for transmitting a recording signal when two similar signals are received by said inputs, means for transmitting a signal representative of a character to be recorded by said recording device to one of said inputs, means operable synchronously with said recording device for transmitting a signal to the other of said inputs representative of the recording character instantly in proximity t-o said recording station, a timing device having a number of timing positions equal to the number of said different recording positions, means including a normally disengaged cyclically operable clutch for advancing said timing device through said timing positions in synchronism with movement of said character recording device through said recording positions, means controlled jointly by said timing device when moving through said timing positions and by a said recording signal for enabling said recording control means, and means for engaging said clutch at any time during advancement of said recording device.

3. In a high speed recording system including a character recording device movable into different recording positions for recording different respective characters at a recording station, means for constantly advancing said recording device repetitively through said positions, normally disabled recording control means for effecting recording by said recording device, and means for advancing a record medium past said recording device; the combination comprising a comparison device having two inputs and an output for transmitting a recording signal when two similar signals are received by said inputs, means for transmitting a signal representative of a character to be recorded by said recording device to one of said inputs, means operable synchronously with said recording device for transmitting a signal to the other of said inputs representative of the recording character instantly in proximity to said recording station, a cyclically operable timing device having a number of timing positions equal to the number of said different recording positions, normally disabled means for advancing said timing device through said timing positions in synchronism with movement of said character recording device through said recording positions, means controlled jointly by said timing device when moving through said timing positions and by said recording signal for enabling said recording control means, means for enabling said timing device advancing means at any time during advancement of said recording device, and means controlled by said timing device after advancement of said timing device through all of said timing positions for causing said record medium advancing means to advance said record medium.

4. In a high speed recording system including a character recording device movable into different recording positions for recording different respective characters at a recording station, means for constantly advancing said recordingdevice repetitively through said positions, normally disabled recording control means for efiecting recording by said recording device, and means for advancing a record medium past said recording device; the combination comprising a comparison device having two inputs and an output for transmitting a recording signal when two similar signals are received by said inputs, means for transmitting a signal representative of a character to be recorded by said recording device to one of said inputs, means operable synchronously with said recording device for transmitting a signal to the other said inputs representative of the recording character instantly in proximity to said recording station, a timing device having a number of timing positions equal to the number of said diiierent recording positions, means including a normally disengaged cyclically operable clutch for advancing said timing device through said timing positions synchronously with said recording device, means controlled jointly by said timing device When moving through said timing positions and by said recording signal for enabling said recording control means, means for engaging said clutch at any time during the advancement of said recording device, and means controlled by said clutch after advancing said timing device through all of said timing positions for causing said record medium advancing means to advance said record medium.

5. In a high speed recording system including a printing drum having a plurality of type elements therearound, a normally disabled printing device for efiecting a printing impression from said drum, means for advancing a record medium between said drum and said printing device, and means for constantly advancing said drum whereby to successively advance different ones of said type elements past said printing device; the combination comprising means for transmitting a coded signal representative of a character to be printed, means operable synchronously with said drum for transmitting a coded signal representative of the type element instantly in proximity to said printing device, means responsive to said last two mentioned means upon transmission of signals representative of a type element and a corresponding character to be printed for conditioning said painting device to effect a printing impression, a timing device having a number of timing positions equal to the number of type elements around said drum, means including a normally disengaged cyclically operable clutch for advancing said timing device through said timing positions synchronously with said drum; means controlled by said timing device when moving through said timing positions to enable said printing device only if said printing device is conditioned, means for engaging said clutch at any time during advancement of said drum, and means controlled by said clutch after advancing said timing device through all of said timing positions for causing said record medium advancing means :to advance said record medium.

6. In a high speed recording system including acharacter recording device movable into different recording positions for recording different respective characters at a recording station, means for constantly advancing said recording device repetitively through said positions, and normally disabled recording control means for effecting recording by said recording device, the combination comprising a comparison circuit having two inputs and an output for transmitting a recording signal when two similar signals are received by said inputs, means for transmitting a signal representative of a character to be recorded by said recording device to one of said inputs, means operable synchronously with said recording device for transmitting an identifying signal of predetermined time period to the other of said inputs representative of the .type element instantly at said recording station, a timing device having a number of timing positions equal to the number of said different recording positions, means including a cyclically operable clutch for advancing said timing device through said timing positions synchronously with said recording device, and means controlled jointly by said timing device when moving through said timing positions and by a said recording signal for transmitting an enabling signal of a shorter duration than that of each of said identifying signals to enable said recording control means.

7. In a high speed recording system including a printing drum having a plurality of type elements therearound, a normally disabled printing device for eflecting a printing impression from said drum, means for advancing a record medium between said drum and said printing device, and means for constantly advancing said drum whereby to successively advance diiierent ones of said type elements past said printing device; the combination comprising means i01- transmitting -a coded signal representative of a character to be printed, means operable synchronously with said drum for transmitting a coded signal representative of the type element instantly in proximity to said printing device, means responsive to said last two mentioned means upon transmission of signals representative of a type element and a corresponding character to be printed for conditioning said printing device to effect a printing impression, a timing device having a number of timing positions equal to the number of type elements around said drum, normally disabled means for advancing said timing device through said timing positions in syn chronism With movement of said type elements past said printing device, means controlled by said timing device when moving through said timing positions to enable said printing device only if said printing device is conditioned, means for enabling said timing device advancing means at any time during advancement of said drum, and means controlled by said timing device after advancement of said timing device through all of said timing positions for causing said record medium advancing means to advance said record medium.

8. In a high speed printing system including a type drum having a plurality of columns of type elements therearound, means for constantly moving said type drum to successively advance said type elements through a printing station, and a plurality of normally disabled printing control devices, each associated with a dilierent column of type and each eifective to transmit an imression of a selected type element onto a record medium at said printing station; the combination comprising a plurality of comparison devices each having a first input and a second input and an output for transmitting an output signal when two similar signals are received by the first and second inputs of a respective comparison device, means for transmitting signals representative of characters to be printed by said printing control devices to respective ones of said first inputs, means operable synchronously with said type drum for transmitting a signal to all said second inputs representative of the type element instantly in proximity to said printing station, a timing device having a number of timing positions equal to the number of said type elements around each of said columns, means including a cyclically operable clutch for advancing said timing device through said timing positions synchronously With said type drum, means controlled jointly by said timing device when moving through said timing positions and by a said output signal for enabling each of said printing control devices, and means for selectively engaging said clutch at any of difierent times during movement of said drum.

9. In a high speed printing system including a type drum having a plurtlity of columns of type elements therearound, means for constantly moving said type drum to successively advance said type elements through a printing station, a plurality of normally disabled printing control devices, each associated with a different column of type and each effective to transfer an impression of a selected type element onto a record medium at said printing station, and means for advancing said record medium relative to said printing station; the combination comprising a plurality of comparison devices, each having a first input and a second input and an output for transmitting an output signal when two similar signals are received by the first and second inputs of a respective comparison device, means for transmitting signals representative of characters to be printed by said printing control devices to respective ones of said first inputs, means operable synchronously with said type drum for transmitting a signal to all said second inputs representative of the type element instantly in proximity to said printing station, a timing device having :a number of timing positions equal to the number of said type characters around each of said columns, means including a cyclically operable clutch for advancing said timing device through said timing positions synchronously with said type drum, and for thereafter actuating said record medium advancing means, means controlled jointly by said timing device When moving through said timing positions and by a said output signal for enabling each of said printing control devices, and means for selectively engaging said clutch at any of different times during movement of said drum.

References Cited in the file of this patent UNITED STATES PATENTS 2,776,618 Hantley Jan. 8, 1957 2,915,966 Jacoby Dec. 8, 1959 2,915,967 Gehiing Dec. 8, 1959 2,915,968 Witt et al Dec. 8, 1959 2,941,188 Flechtner June 14, 1960 2,954,731 Durand et a1 Oct. 4, 1960 

1. IN A HIGH SPEED RECORDING SYSTEM INCLUDING A CHARACTER RECORDING DEVICE MOVABLE INTO DIFFERENT RECORDING POSITIONS FOR RECORDING DIFFERENT RESPECTIVE CHARACTERS AT A RECORDING STATION, MEANS FOR CONSTANTLY ADVANCING SAID RECORDING DEVICE REPETITIVELY THROUGH SAID POSITIONS, AND NORMALLY DISABLED RECORDING CONTROL MEANS FOR EFFECTING RECORDING BY SAID RECORDING DEVICE; THE COMBINATION COMPRISING A COMPARISON DEVICE HAVING TWO INPUT AND AN OUTPUT FRO TRANSMITTING A RECORDING SIGNAL WHEN TWO SIMILAR SIGNALS ARE RECEIVED BY SAID INPUTS, MEANS FOR TRANSMITTING A SIGNAL REPRESENTATIVE OF A CHARACTER TO BE RECORDED BY SAID RECORDING DEVICE TO ONE OF SAID INPUTS, MEANS OPERABLE SYNCHRONOUSLY WITH SAID RECORDING DEVICE FOR TRANSMITTING A SIGNAL TO THE OTHER OF SAID INPUTS REPRESENTATIVE OF THE RECORDING CHARACTER INSTANTLY IN PROXIMITY TO SAID RECORDING STATION, A CYCLICALLY OPERABLE TIMING DEVICE HAVING A NUMBER OF TIMING POSITIONS EQUAL TO THE NUMBER OF SAID DIFFERENT RECORDING POSITIONS, NORMALLY DISABLED MEANS FOR ADVANCING SAID TIMING DEVICE THROUGH SAID TIMING POSITIONS IN SYNCHRONISM WITH MOVEMENT OF SAID CHARACTER RECORDING DEVICE THROUGH SAID RECORDING POSITIONS, MEANS CONTROLLED JOINTLY BY SAID TIMING DEVICE WHEN MOVING THROUGH SAID TIMING POSITIONS AND BY A SAID RECORDING SIGNAL FOR ENABLING SAID RECORDING CONTROL MEANS, AND MEANS FOR ENABLING SAID TIMING DEVICE ADVANCING MEANS AT ANY TIME DURING ADVANCEMENT OF SAID RECORDING DEVICE. 